Good for the environment and health Biodegradable plant protection product developed

Without risks and side effects: Biodegradable plant protection product developed

Plant protection products have a toxic effect on harmful organisms. However, the effect of most remedies is not limited to these. Other animal and plant species can also be damaged. In addition, some of the chemicals can harm human health. Now there is an alternative: German researchers have developed a biodegradable plant protection product.

Massive use of pesticides

Plant protection products are widely used in agriculture and in relatively large quantities in the environment to protect plants from harmful organisms. "On average, about nine kilograms of pesticides and 2.8 kilograms of active substances are used per year on one hectare of agricultural land," reports the Federal Environment Agency on its website. The chemicals can also have negative effects on other animal and plant species as well as on human health. A team from the Technical University of Munich (TUM) has now developed an alternative: A biodegradable active substance keeps pests away without poisoning.

Plant protection products not only kill pests but also endanger bees and other beneficial insects. Researchers have now developed a biodegradable agent that keeps pests away without poisoning them. (Image: farbkombinat / fotolia.com)

Insecticides not only kill pests

According to a TUM statement, traditional crop protection products are killer: Synthetic insecticides not only kill pests but also endanger bees and other beneficial insects such as beetles, butterflies and grasshoppers.

In addition, they affect the biodiversity in soils and endanger many waters such as lakes and rivers.

In addition, it has long been known that pesticides can harm your health. They disturb the hormone balance of the body and can damage the human immune system. Nevertheless, crop protection products are not uncommon in food.

The use of such chemicals has therefore been highly controversial for many years.

Keep away instead of poisoning

"It's not just about the bees, it's about the survival of humanity," says Professor Thomas Brück, owner of the Werner Siemens Chair of Synthetic Biotechnology, TU Munich.

"Without the bees pollinating a variety of plants, not only would our supermarket shelves be pretty empty, but within a short time, it would no longer be possible to supply the world's population with food."

Brück and his team have now developed an insect repellent that they claim to be biodegradable and environmentally safe.

Sprayed on plants, it works like a mosquito repellent, which bathers apply in summer: it spreads a smell that keeps unwanted insects away.

"With our approach, we are enabling a fundamental change in crop protection," says Brück. "Instead of spraying poison, which always endangers also useful species, we deliberately pollute only the pests."

Bacteria as chemical factories

The example of the Munich researchers was the tobacco plant, which produces cembratrienol, or CBT-ol, in its leaves. With this molecule, the plant protects itself from pests.

Using synthetic biotechnology tools, the research team isolated those sections of the genome of the tobacco plant responsible for the formation of CBT-ol molecules.

Subsequently, they incorporated these into the genetic material of coliform bacteria. Fed with wheat bran, a by-product of grain mills, the genetically modified bacteria now produce the desired active ingredient.

Efficiency on both a small and a large scale

"The biggest challenge in production was separating the active ingredients from the nutrient solution at the end of the process," explains Mirjana Minceva, Professor of Biothermodynamics at TUM Campus Weihenstephan.

The solution brought the centrifugal separation chromatography. The process is highly efficient and also works on an industrial scale, but has never before been used for the separation of products from fermentation processes.

Effective against bacteria too

According to preliminary studies, the CBT spray is non-toxic to insects and still protects effectively against aphids. Since it is biodegradable, it does not accumulate.

In addition, the bioactivity tests showed that cembratrienol has an antibacterial effect on gram-positive bacteria.

It could therefore be used as a disinfectant spray that acts specifically against pathogens such as Staphylococcus aureus (MRSA pathogen), Streptococcus pneumoniae (pathogen pneumonia) or Listeria monocytogenes (causative agent of listeriosis).

The results of the scientists were published in the journal "Green Chemistry". (Ad)